1. Field of the Invention
The present invention relates generally to an original document reading device, and relates more particularly to an original document reading device disposed in a photocopier or facsimile machine, for example, for scanning an original document on a document table.
2. Background Information
The timing at which the pickup roller picks an original document from the document table in a conventional original document reading device is controlled to the moment at which the roller contacts the top of the document held on the document table after the pickup roller begins descending. This shortens the time between the start of pickup roller movement and paper feeding, and thus improves the paper feed rate.
Another example of a conventional original document reading device has a stack height sensor for sensing the thickness of a stack of original documents placed on the document table. This original document reading device determines how far to move the lift plate based on the detected stack height, and then drives and stops a motor to raise or lower the lift plate the determined distance and thus prevent damage to the device when a problem with the lift plate is detected.
To improve the ease of use for the operator, the operating mode of the original document lifting member in yet another example of a conventional original document reading device can be selectively set to either of two modes: a first operating mode in which the original document lifting member rises immediately after an original is placed on the paper feeding table, and a second operating mode in which the original document lifting member rises when the start button is pressed after detecting that an original document is on the paper feeding table.
These conventional original document reading devices address the need to improve the paper feed rate, prevent damage to the document table, and improve the ease of use to some degree, but these reading devices are not necessarily easy to use.
The present invention is directed to these problems, and an object of the invention is to provide an original document reading device that is easier for the operator to use.